The present invention relates to a switch device, and more particularly, to a non-contact type engine start switch device.
In recent years, engine start systems having a “smart ignition” function have been used in automobiles to improve their security level and convenience. As one example, Japanese Laid-Open Patent Publication No. 2001-289142 discloses a control device for use in a vehicle having a smart ignition function. The control device communicates with a portable device held by a driver. The smart ignition function permits an engine of a vehicle to be started just by bringing the portable device into the vehicle. The engine, which is then permitted to start by the security system, can be started by operating an engine start switch.
The driver of the vehicle with the smart ignition function is not required to perform a complicated key operation to start the engine. The driver can start the engine simply by bringing the portable device in the vehicle and operating the engine start switch. In this way, the smart ignition function provides improved convenience. Further, the engine is not permitted to start unless the driver holds the portable device, which is far more difficult to copy than a conventional mechanical key. The smart ignition function also provides improved security.
A contact type switch is presently used as the engine start switch. When the engine start switch is operated, for example, in a low-temperature environment, starting of the engine may be delayed by chattering, which uniquely occurs in a contact type switch. This disadvantageous feature of contact type switches have made it difficult to render the engine start switch to have high reliability in starting the engine.